Anterior spinal vessel protector

ABSTRACT

A protective system for facilitating revision surgery includes a protective pad with a base portion and an overlying portion spaced apart from the base. A fluid pocket is formed between the base portion; and the overlying portion. The protective system prevents formation of adhesions or scar tissue in the area occupied by the protective pad. Thus a clean plane is obtained during revision surgery on the patient through an incision in the fluid pocket.

FIELD OF THE INVENTION

This invention relates to surgical devices and, more particularly, todevices used to facilitate revision surgery implicating vulnerableanatomical parts.

BACKGROUND

Spinal disorders requiring surgical procedures are well known. Thelumbar region of the human anatomy, for example, is a frequent site ofspinal disorders which may be corrected by surgical procedures carriedout anteriorly of the lumbar vertebrae including, for example, surgicalprocedures involving disc removal and/or replacement.

In anterior spinal surgical procedures, the initial surgery is throughan unscarred and substantially clear path to the surgical site. Inrevision surgery, however, the path to the surgical site has typicallydegraded as a result of the previous surgery resulting in scarring andother developments which may interfere with the revision surgery.

Moreover, the present technology in spinal surgeries is typicallyfocused on anterior insertion of intervertebral prostheses, and otheranterior surgical procedures. Consequently, the potential of anteriordislocation of prostheses and vertebral structures as well as potentialinjury to the significant blood vessels located in proximity to thespine is increased.

U.S. Pat. No. 6,475,219 issued to Alexis P. Shelekov on Nov. 5, 2002,addressed the aforementioned conditions. The '219 patent, the teachingsof which are herein incorporated by reference, discloses a method anddevice for protecting major vessels and other anatomical parts fromcomplications as a consequence of anterior spinal surgical procedures.In particular, the '219 patent discloses a method for protecting majorblood vessels, such as the aorta and the vena cava, and providing someprotection against anterior dislocation of vertebral bodies adjacentthese vessels. The '219 patent also provides for minimizing theformation of adhesions or unwanted joining of certain tissues and bodystructures to each other pursuant to anterior spinal surgery.

The '219 patent provides a significant improvement in protection ofvulnerable anatomical parts in areas subject to revision surgery.Nonetheless, a need exists for a device which further simplifiesrevision surgeries, particularly in the area of vulnerable body parts.It would be advantageous if the device facilitated location of thetargeted surgical area. Moreover, it would be beneficial if the devicecould be conveniently interposed between the spinal column andanatomical parts, particularly, major blood vessels such as the aortaand the vena cava, so that the anatomical parts are protected during asurgical procedure and/or are not subject to the development ofadhesions or tissue which may produce complications during revisionsurgery.

SUMMARY

A protective system and method is disclosed. In accordance with onemethod according to the invention, a patient is prepared for a firstsurgical procedure. A first incision is made through the skin of thepatient in accordance with the first surgical procedure and a targetarea for the first surgical procedure is exposed through the firstincision. A step of the first surgical procedure is then performed onthe target area for the first surgical procedure. Thereafter, aprotective pad with a fluid pocket is placed between a vulnerableanatomical part and the target area for the first surgical procedure andthe first incision is closed in accordance with the first surgicalprocedure with the protective pad between the vulnerable anatomical partand the target area.

In one embodiment, a protective system for facilitating revision surgeryincludes a protective pad with a base portion of biocompatible materialand an overlying portion of biocompatible material spaced apart from thebase, the base portion and the overlying portion forming at least aportion of a fluid pocket. The system further includes at least one boneanchor for affixing the protective pad to a bone.

The above-described features and advantages, as well as others, willbecome more readily apparent to those of ordinary skill in the art byreference to the following detailed description and accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a protective pad with a telltale madein accordance with principles of the present invention;

FIG. 2 shows a cross-sectional view of the protective pad of FIG. 1taken along the line A-A of FIG. 1;

FIG. 3 shows a side perspective view of a spinal column upon which theprotective pad of FIG. 1 may be placed in accordance with principles ofthe present invention;

FIG. 4 shows a partial perspective anterior view of a prevertebral spaceincluding anatomical parts which may be encountered during a surgicalprocedure in accordance with principles of the present invention;

FIG. 5 shows a partial schematic view of a portion of the prevertebralspace of FIG. 4 superimposed upon a portion of the spinal column of FIG.3 to illustrate the location of some of the anatomical parts of FIG. 4relative to the spinal column;

FIG. 6 shows a partial anterior perspective view of a protective padattached to the spinal column of FIG. 3 underneath the aorta and thevena cava of a patient;

FIG. 7 shows a cross-sectional view of the protective pad of FIG. 6taken along the line B-B of FIG. 6 wherein the fluid pocket of theprotective pad is located between the spinal column and the aorta andthe vena cava of the patient;

FIG. 8 shows a partial anterior perspective view of the protective padof FIG. 6 with incisions made therein to form a leaf;

FIG. 9 shows a partial anterior perspective view of the protective padof FIG. 6 with the leaf retracted so as to retract the aorta and thevena cava of the patient and to expose a portion of the base of theprotective pad;

FIG. 10 shows a perspective view of an alternative protective pad with atelltale made in accordance with principles of the present inventionthat separates vulnerable anatomical parts from a target area of a spineand further extends between the vulnerable anatomical parts tofacilitate access to a target area through the space between theanatomical parts;

FIG. 11 shows a cross-sectional view of the protective pad of FIG. 10taken along the line C-C of FIG. 10 showing concave trailing portionsextending away from the front end of the protective pad;

FIG. 12 shows a top plan view of the protective pad of FIG. 10;

FIG. 13 shows a cross-sectional view of the protective pad of FIG. 10taken along the line C-C of FIG. 10 in position between the common ileacarteries and veins of the patient;

FIG. 14 shows a partial anterior perspective view of the protective padof FIG. 10 located on a patient with incisions made in the overlyingportion of the protective pad to form a leaf;

FIG. 15 shows a partial anterior perspective view of the protective padof FIG. 14 with one leaf retracted so as to retract one common ileacvein and one common ileac artery of the patient and to expose a portionof the base of the protective pad; and

FIG. 16 shows a partial anterior perspective view of the protective padof FIG. 14 with two leafs retracted so as to retract both common ileacveins and both common ileac arteries of the patient and to expose twoportions of the base of the protective pad.

DETAILED DESCRIPTION

FIG. 1 depicts a protective pad 100. The protective pad 100 has agenerally rectangular shape with four fastener areas 102, 104, 106 and108 located at each of the four corners of a base 110 of the protectivepad 100. In this embodiment, the fastener areas 102, 104, 106 and 108include bone fastener holes 112, 114, 116 and 118. The bone fastenerholes 112, 114, 116 and 118 may be used with a bone fastener such as ascrew, peg or nail to attach the protective pad 100 to a bone.Alternatively, the protective pad 100 may be sutured in place.

As shown in FIG. 2, an overlying portion 120 extends above a portion ofthe base 110. The overlying portion 120 and the base 110 define a fluidpocket 122. In the embodiment of FIG. 2, the overlying portion 120 andthe base 110 are configured to provide an impermeable barrier about thefluid pocket 122. Accordingly, fluid within the fluid pocket 122 is notallowed to exit the fluid pocket 122. Additionally, fluids outside ofthe protective pad 100 are not allowed to enter the fluid pocket 122.The protective pad 100 further includes a telltale 124 which in thisembodiment extends from the base 110. The telltale 124 includes a marker126.

The overlying portion 120, the base 110 and the telltale 124 are formedfrom a flexible biocompatible material or subdermal implant material,such as Silastic brand silicone rubber or similar organosiloxanepolymers. The fluid pocket 122 is filled with a biocompatible fluidwhich may be liquid or gaseous. In one embodiment, carbon dioxide gas isused. Other biologically inert gasses may be used in alternativeembodiments. The fluid pocket 122 may be configured to provide a thinlayer of fluid between the overlying portion 120 and the base 110 or toprovide a more substantial separation between the overlying portion 120and the base 110 as shown in FIG. 2. The marker 126 in the embodiment ofFIG. 1 includes a radiodense material so as to be readily identifiedusing radiography.

The present invention is particularly well suited for use in surgerieson the spinal column of a patient. Referring to FIG. 3, a spinal column128 of a human being is illustrated. In the drawing figures, certainanatomical details may be omitted or shown somewhat schematically in theinterest of clarity. The spinal column 128 includes a cervical region130, a dorsal region 132, a lumbar region 134 and a pelvic region 136.

Two of the regions of the spinal column 128 that are most commonlyoperated on are the lumbar region 134 and the pelvic region 136. Inthese regions, the area including lumbar L4 138 and lumbar L5 140 andthe area including lumbar L5 140 and the sacrum 142 are the areas towhich most spinal operations are directed.

One surgical approach that is used when performing a surgical procedureon the above described areas is identified as the PararectalRetroperitoneal Approach. In this approach, which may be used forprocedures such as a disc removal or disc prosthesis installation, theskin of the patient is incised in a curved line over the lateral borderof the rectus muscle of the patient. Through this incision, theprevertebral space of the patient is exposed.

FIG. 4 depicts various anatomical parts that are located within oradjacent to a prevertebral space 144. As depicted therein, the vena cava146 extends generally along a line directly above the spinal column (notshown in FIG. 4). The vena cava 146 receives blood from the common iliacveins 148 and 150 and their respective branches. The abdominal aorta 152begins to the right of the vena cava 146 as viewed in FIG. 4 and extendsover the top of the vena cava 146 lower down in the prevertebral space144. The abdominal aorta 152 provides blood to two common iliac arteries154 and 156 and their respective branches.

The vena cava 146, the common iliac veins 148 and 150 and theirrespective branches, the abdominal aorta 152, and the common iliacarteries 154 and 156 and their respective branches are anterior to, andgenerally co-linear with, the spinal column 128 as shown in FIG. 5.Accordingly, when using the Pararectal Retroperitoneal Approach, atleast some of these blood vessels must be moved to the side to exposethe targeted area of the spinal column 128. During an index surgicalprocedure, movement of the blood vessels is accomplished by retractingthe vena cava 146 and the abdominal aorta 152 to one side to expose thelumbar L4 138 and lumbar L5 140 vertebrae or by spreading the commoniliac vein 148 and the common iliac artery 154 apart from the commoniliac vein 150 and the common iliac artery 156 to expose the area aboutthe lumbar L5 140 and the sacrum 142. Depending on the actual locationof the veins and arteries of a particular patient and the area beingtargeted, branches of the iliac vessels may need to be moved in additionto or in place of the iliac vessels.

The blood vessels and surrounding tissue exhibit sufficient flexibilityand looseness for the amount of retraction required to access areasusing the Pararectal Retroperitoneal Approach during an initial surgeryon a target area. After the initial surgery, however, scar tissue and/oradhesions may form about the surgical path and restrict the flexibilityand looseness of the anatomical parts around the path to and in the areaof the target area. To facilitate a revision surgery in the same area asthe index surgery, a protective pad may be used to reduce complicationsresulting from scar tissue and/or adhesions. Preferably, the protectivepad is attached to the spinal column 128 during the initial surgicaloperation. More preferably, the protective pad is attached after aprocedure has been conducted on a target area and before the bloodvessels or other anatomical parts are released from a retractedposition.

FIG. 6 depicts a portion of the prevertebral space 144 after the bloodvessels have been released from retraction. The protective pad 158 isattached to the lumbar L4 138 vertebra with two fasteners 160 and 162which are inserted through the fastener areas 164 and 166, respectively.Preferably, holes are provided in the fastener areas 164 and 166 whichallow the shafts (not shown) of the bone fasteners 160 and 162, which inthis embodiment are screws, to pass through the protective pad 158.Similarly, the protective pad 158 is attached to the lumbar L5 140vertebra with two fasteners 168 and 170 which are inserted through thefastener areas 172 and 174, respectively.

In this configuration, the base 176 of the protective pad 158 is locatedadjacent to the spinal column 128 and an overlying portion 178 and afluid pocket 180 are located beneath the vena cava 146 and the abdominalaorta 152 of the patient as shown in FIG. 7. In a preferred embodiment,the protective pad 158 is selected from a kit of protective pads havingdifferent sizes. This allows a pad to be selected with a length thatextends, in this example, from about the mid-point of the lumbar L4 138vertebra to about the mid-point of the lumbar L5 140 vertebra.Additionally, the width of the protective pad 158 is selected to ensurethe fluid pocket 180 extends outwardly from the vena cava 146 and theabdominal aorta 152 on at least one side as is discussed more fullybelow. In this embodiment, FIG. 7 shows that the fluid pocket 180extends outwardly from both the vena cava 146 and the abdominal aorta152 in a medial-lateral direction. The overall width of the protectivepad 158 is preferably selected to provide complete coverage of thetargeted vertebrae from psoas to psoas.

The telltale 182 extends away from the protective pad 158 and includes amarker 184 which may be similar to the marker 126 of FIG. 1. To aid inrapidly locating the telltale 182 during a revision surgery, the endportion with the marker 184 may conveniently be tacked to the rectus ofthe patient or affixed to another readily identifiable location by someother means.

Accordingly, during a revision surgery on or near the targeted area ofthe first procedure, radiography is used to identify the location of themarker 184 on the telltale 182. Then, after preparing the incision areain accordance with a proper surgical protocol, an incision in the skinof the patient is made and the telltale 182 is located based upon theradiography. In this embodiment, the telltale 182 is shown attached tothe base 176. Alternatively, the telltale 182 may be attached to theoverlying portion 178. In the event the telltale 182 does not interferewith the remaining steps of the surgical procedure, the telltale 182 mayremain attached to the patient. Alternatively, if the telltale 182 isattached to the overlying portion 178 or will interfere with ensuingsteps, the telltale 182 is detached from the patient.

In either event, the surgeon then follows the telltale 182 to theprotective pad 158. After lysis of adhesions on the portion of the pad158 on the side opposite the direction of desired retraction, alongitudinal incision 186 is made through the overlying portion 178along a line adjacent to the vena cava 146 or the abdominal aorta 152 asshown in FIG. 8. The width of the fluid pocket 180 preferably extendsoutwardly of both the vena cava 146 and the abdominal aorta 152. Thisallows a surgeon to select the direction in which the blood vessels willbe retracted based upon the particular condition of the patient. If thefluid pocket only extends outwardly of one of the two blood vessels,then the incision is preferably made to allow retraction of the bloodvessels in a direction opposite the direction in which the fluid pocketextends outwardly of the one of the two blood vessels.

The overlying portion 178 may then be manipulated to retract theadjacent blood vessel away from the longitudinal incision 186 allowing atransverse incision 188 to be made in the overlying portion 178 at oneend of the protective pad 158 and another transverse incision 190 alongthe opposite end of the protective pad 158. The longitudinal incision186 and the transverse incisions 188 and 190 form a leaf 192.

Once the leaf 192 is sufficiently formed, a retractor is placed throughthe longitudinal incision 186 and into the fluid pocket 180. Theretractor is used to move the leaf 192 in a direction away from thelongitudinal incision 186. If needed, any of the incisions may befurther extended during retraction. As shown in FIG. 9, the leaf 192,acting as a protective layer, is used to retract the vena cava 146 andthe abdominal aorta 152 to reveal an exposed portion 194 of the base176. An incision may then be made through the exposed portion 194 toreveal the targeted area.

As stated above, when using the Pararectal Retroperitoneal Approach inthe area about the lumbar L5 140 and the sacrum 142, the common iliacvein 148 and the common iliac artery 154 are spread apart from thecommon iliac vein 150 and the common iliac artery 156. Accordingly, itis desirable to form two different leaves from the protective pad, oneleaf for each set of blood vessels. The protective pad 158 may be usedin this setting with appropriate modification of the location of thelongitudinal cut to a central area and using transverse cuts to from twoleaves. An alternative protective pad that may be used is the protectivepad 200 shown in FIG. 10.

The protective pad 200 has a generally rectangular base 202 with fourfastener holes 204, 206 208 and 210 located at each of the four corners.An overlying portion 212 is attached to the base 202 so as to define afluid pocket 214 (see FIG. 11). The overlying portion 212 may beattached to the base 202 by use of an adherent or other acceptablemethod such as ultrasonic welding. The fluid pocket 214 is generallyplough shaped with a narrow end portion 216. Two trailing portions 218and 220 extend away from the end portion 224 and diverge from eachother. The trailing portions 218 and 220 join a wide end portion 222 soas to form a generally triangular shape when viewed from above the fluidpocket 214 (see FIG. 12). The protective pad 200 further includes atelltale 224 which in this embodiment extends from the narrow endportion 216. The telltale 224 includes a marker 226.

The protective pad 200 is implanted on a bone such as the spinal column128 following essentially the same steps set forth above with respect tothe protective pad 158. The procedure for performing a revision surgeryin the vicinity of the implanted protective pad 200 is the same as themethod set forth above with respect to protective pad 158 until thetelltale 224 is followed to the protective pad 200.

The protective pad 200 is configured such that when it is implanted inthe area of the lumbar L5 140 and the sacrum 142, the common iliac vein148 and the common iliac artery 154 are spaced apart from the commoniliac vein 150 and the common iliac artery 156 by the plough shapedfluid pocket 214 as shown in FIG. 13. The protective pad 200 is furtherconfigured such that the overlying portion 212 extends away from thespinal column 128 to about the same height as the aorta is located abovethe spinal column 128. Accordingly, when the telltale 224 is tracked tothe protective pad 200, at least some of the overlying portion 212 willbe exposed between the iliac vein 148 and the common iliac artery 154 onone side and the common iliac vein 150 and the common iliac artery 156on the other side as shown in FIG. 14.

The area about the protective pad 200 is then prepared for retraction ofthe blood vessels. In a preferred approach, a longitudinal incision 228is made through the overlying portion 212 along a line between thenarrow end portion 216 and the wide end portion 222. Typically, thelongitudinal incision 228 will be made approximately along thecenterline of the overlying portion 212. Depending on the conditions fora particular patient, the location of the incision may be adjusted toone side or the other. Transverse incisions 230 and 232 are made alongthe wide end portion 222. Of course, the order of the incisions may bemodified. The longitudinal incision 228 and the transverse incisions 230and 232 form leafs 234 and 236.

Once a leaf is sufficiently formed, a retractor (not shown) is placedthrough the longitudinal incision 228 and into the fluid pocket 214. Theretractor is used to move one of the leafs 234 or 236 in a directionaway from the longitudinal incision 228. As shown in FIG. 15, the leaf234 is positioned against the common iliac vein 148 and the common iliacartery 154 and their branches. The leaf 234 thus provides protection tothe common iliac vein 148, the common iliac artery 154 and theirrespective branches. The leaf 234 may further be used to retract thecommon iliac vein 148 and the common iliac artery 154 and their branchesto reveal exposed portion 238 of the base 202.

If desired, a second retractor (not shown) may be used to move the otherof the leafs 234 or 236 in a direction opposite of the direction of thefirst retraction. Thus, as shown in FIG. 16, the leaf 236 is positionedagainst the common iliac vein 150 and the common iliac artery 156 andtheir branches. The leaf 236 thus provides protection to the commoniliac vein 150, the common iliac artery 156 and their respectivebranches. The leaf 234 may further be used to retract the common iliacvein 150 and the common iliac artery 156 and their branches to revealportion 240 of the base 202. An incision may then be made through thebase 202 using one or both of the exposed areas 238 and 240 to revealthe targeted area.

While the present invention has been illustrated by the description ofexemplary processes and system components, and while the variousprocesses and components have been described in considerable detail,applicant does not intend to restrict or in any way limit the scope ofthe appended claims to such detail. Additional advantages andmodifications will also readily appear to those ordinarily skilled inthe art. The invention in its broadest aspects is therefore not limitedto the specific details, implementations, or illustrative examples shownand described. Accordingly, departures may be made from such detailswithout departing from the spirit or scope of applicant's generalinventive concept.

1. A protective system for facilitating revision surgery comprising: aprotective pad having a base portion and a retraction portion, theprotective pad including at least one fastener hole structure definingat least one fastener hole; and at least one bone anchor configured tocooperate with the at least one fastener hole structure to affix theprotective pad to a bone, wherein (i) the base portion defines a firstinternal surface, and (ii) the retraction portion defines a secondinternal surface, wherein the protective pad is configured to be movedfrom a first configuration to a second configuration, wherein, when theprotective pad is in the first configuration, the retraction portion islocated in relation to the base portion at a first relative position inwhich the retraction portion overlays the base portion to define atleast part of a fluid pocket between the first internal surface and thesecond internal surface, wherein, when the protective pad is in thesecond configuration, the retraction portion is located in relation tothe base portion at a second relative position in which the retractionportion is retracted away from the base portion so as to expose thefirst internal surface, wherein the fluid pocket is sealed such thatfluid is not allowed to flow into or out of the fluid pocket.
 2. Theprotective system of claim 1, wherein the fluid pocket contains abiologically inert gaseous fluid.
 3. The protective system of claim 2,wherein the gaseous fluid is carbon dioxide.
 4. The protective system ofclaim 1, further comprising: a telltale extending from the protectivepad.
 5. The protective system of claim 4, wherein the telltale comprisesa radio dense material.
 6. The protective system of claim 1, wherein thefluid pocket comprises: an end portion; a first trailing portionextending from the end portion; and a second trailing portion extendingfrom the end portion and diverging from the first trailing portion. 7.The protective system of claim 1, wherein: when the protective pad is inthe first configuration, the second internal surface of the retractionportion faces toward the first internal surface of the base, and whenthe protective pad is in the second configuration, at least a portion ofthe second internal surface of the retraction portion faces away fromthe first internal surface of the base.
 8. The protective system ofclaim 1, wherein both the retraction portion and the base portion areformed from a flexible biocompatible material.
 9. The protective systemof claim 1, wherein the retraction portion and the base portion are bothformed from an organosiloxane polymer material.